1. Field of the Invention
The present invention relates to a rope traction elevator with an elevator drive, and comprises a gear with a traction sheave, a motor, a brake, and suspension elements which pass over the traction sheave to provide vertical motion to an elevator car, preferably with a counterweight. The motor of the elevator drive is in an upright position.
2. Discussion of the Prior Art
An elevator drive of the type mentioned is known from German reference DE 37 37 773 C2. The purpose of this construction is to make it easy to assemble the gear, and to permit rapid mounting and dismounting of the motor, while keeping the bearings aligned during the process. The motor, which is in an upright position on top of the gear, has a drum brake at its upper end.
With today's high level of thermal load on motor windings, the occurrence of a fault in the windings due to an overload appears to be more probable than a mechanical defect in the gear. If a defective motor has to be replaced, the brake on top of the motor also has to be removed together with the defective motor. A prerequisite for this operation is that the car and counterweight must first be secured against unbraked movement, for example by applying clamps to the ropes and/or supporting the counterweight in the hoistway. This procedure is time-consuming and carries the risk of accidents.
The German utility model 1 918 376 discloses an elevator drive consisting of a worm gear and a motor which is also in an upright position, but in which the motor is an external rotor motor and whose cylindrical external surface simultaneously serves as a brake drum. With this drive the brake also has to be removed when the motor is replaced, which gives rise to the same disadvantageous effect as already described above. Furthermore, the large gyrating mass resulting from the external rotor principle can have a negative effect on the acceleration and deceleration of the elevator car.
In both of the drives mentioned, the small size of the motors in relation to the size of the gear leads to the conclusion that these drives are designed only for relatively low power output. If a motor for the medium power range is used which has a higher power output and is therefore larger, the horizontal dimensions of the motor may be greater than those of the gear base, which has negative consequences for the range of possible layouts.